The present invention relates to a bumper for a motor vehicle, and, more particularly, to a bumper with a crossmember fixed to the body and with an impact-confronting collision part. Furthermore, the bumper includes deformation members arranged between the collision part and the crossmember, at least in the region of support points. The impact-confronting collision part is secured to the crossmember via fastening bolts passing through the deformation members in the longitudinal direction of the vehicle, continence to hold the bumper.
A bumper arrangement is known as shown in German Offenlegungsschrift 2,413,772, in which energy absorption by prestressed honeycombed deformation members occurs in response to a relatively sharp impact and in which, after the effect of an impact, a loose fastening point indicates that the associated deformation member is permanently deformed and needs replacing.
The object of the present invention is to provide, while preserving the indication of a deformation member permanently deformed after the effect of an impact which is capable of exerting an energy-absorbing effect, even at relatively low collision speeds, and in which, for a further increase in the range if energy absorption, the deformation members provide their full energy absorption capacity as required.
The foregoing object has been achieved in accordance with the present invention by providing, an impact-confronting collision part in the form of a viscoplastic material trim part encasing, at least in the region of support points, a core of elastically deformed foam. With the exception of the region of the support points, the bumper has a gap on the energy-absorber side relative to the crossmember fixed to the body. Each fastening is surrounded by a spear sleeve bumper. The elastically deformable foam, which after some time resumes its initial position, exerts its energy-absorbing effect even in response to only small impacts, and after its energy-absorption capacity has been exhausted the permanent deformation of the deformation members, of which the extent of deformation is not restricted by an applied prestress, commences. The gap formation adjacent to the support points ensures that a permanently deformed deformation member is indicated by a loose fastening, so that a replacement of the corresponding deformation member can be carried out.